A pH-dependent colon-targeted oral drug delivery system using methacrylic acid copolymers. II. Manipulation of drug release using Eudragit (R) L100 and Eudragit S100 combinations

Tablets containing mesalazine as a model drug were coated using various com binations of two methacrylic acid copolymers, (Eudragit(R) L100 and Eudragi t S100) by spraying from aqueous systems. The Eudragit L100-Eudragit S100 ( w/w) combinations studied were 1:0, 4:1, 3:2, 1:1, 2:3, 1:4, 1:5, and 0:1. The coated tablets were rested in vitro for their suitability for pH-depend ent colon-targeted oral drug delivery. The dissolution profiles of the drug obtained from the studied tablets demonstrate that the release of the drug could be manipulated by changing the Eudragit L100-Eudragit S100 ratios in the combinations within the pH range between 6.0 and 7.0 in which the indi vidual polymers are soluble, and a coating formulation consisting of a comb ination of the two polymers can overcome the issue of high gastrointestinal (GI) pH variability among individuals. The results also demonstrate the fe asibility of using using aqueous dispersions of Eudragit L100-Eudragit S100 combinations for coating tablets for colon-targeted delivery of drugs, and that the formulation can be adjusted to deliver drug(s) at any other desir able site of the intestinal region of the GI tract in which pH of the fluid is within the range 6.0 to 70. For colon-targeted delivery of drugs, the p roposed combination system is superior to tablets coated with either Eudrag it L100 or Eudragit S100 alone.